Classification of Organisms
Fill It In …
Write a definition for the word “classify”.
Isn’t every living thing either a
plant or an animal?
• Aristotle is credited
with the first true
classification system.
• He grouped all living
things into two basic
groups: plant and
animal
OR
Carlos Linnaeus
• Linnaeus further
classified plants and
animals by dividing
them into related
groups.
• He used the Latin
language, because
Latin was no longer
spoken
conversationally and
thus was less likely to
change.
Carlos Linnaeus
• He first grouped related
organisms.
• He called this a genus.
• For example, all of the
dog-like creatures were
grouped as the genus
Canis.
Carlos Linnaeus
• He next gave every different
type of organism in the group
a specific name, which he
called species.
• For example, the dog became
Canis familiaris and the wolf
Canis lupus.
• Notice the genus is capitalized but
the specie begins with a lower case
letter.
• Both are italicized or underlined.
Carlos Linnaeus
• Every organism was
given a two-word name,
the genus and specie.
• This practice of binomial
nomenclature continues
today, giving each
organism a “scientific
name”.
Loxosceles reclusa
(Brown Recluse)
Carlos Linnaeus
• The benefit of binomial
nomenclature includes
eliminating confusion due
to common names (ex.
cottonmouth and water
moccasin are actually the
same animal) and allows
scientists around the
world to more easily
communicate.
Microbes?
• Even after the
microbial world was
discovered, the two
“kingdom” system
continued.
• (Yes, science can be
very slow to change.)
plant or animal?
Whittaker
• As knowledge of the
diversity of organisms
increased, Whittaker
(in 1969) expanded
classification to
include five kingdoms.
Taxonomy
• The science of classification, taxonomy, now
allowed scientists to assign seven levels of taxa
to living organisms.
Fill It In …
MEMORY AID!
KPCOFGS-
Taxonomy
• The kingdom is the
most general of these
seven taxa, thus the
kingdom would
contain the greatest
number of organisms.
Taxonomy
• Specie is the most specific of
these seven taxa, thus the
specie would contain only
one type of organism.
• A specie is defined as a
group of organisms which
can interbreed and produce
fertile offspring.
Fill It In …
How are the terms “kingdoms” and “taxa”
related?
Taxonomy
• Today, we use three
domains, which are
divided into six
kingdoms.
• These domains are
based on new
information about
possible evolutionary
relationships.
Fill It In …
Draw a picture for each of the six kingdoms
and label with the kingdom name:
Fill It In …
The History of Classification:
Linnaeus had ____ kingdoms
Whittaker used ____ kingdoms
Today we use ____ kingdoms
Let’s Play …
1.
2.
3.
4.
5.
6.
7.
8.
Which level is the most general?
The most specific?
At what taxonomic level do the
dog and human become
different?
What is the family name of the
dog?
Which organism is most closely
related to the dog?
What is the scientific name of
the dog?
A genus is composed of a
number of related ___?
A group of related phyla are
called a ___?
Which taxon contains the largest
number or organisms?
What happens when you find an
unknown organism?
• Dichotomous keys are
tools that use a series of
paired statements and
visible characteristics of
the organism.
• Of course, a dichotomous
key is only useful if the
organism has already
been classified and given
a scientific name.
What happens when you find an
unknown organism?
• Always start at statement
1 (or the beginning point).
• Decide which path best
describes the organism
(Statement A or
Statement B)
• Follow that path to find
the next choice (Go to …)
• When you can go no
further, you will find the
name!
Fill It In …
Answers:
1.
2.
3.
4.
5.
What happens when you find an
unknown organism?
• If the organism has
NOT been classified,
taxonomists must
begin the process of
classification.
• In order to correctly
classify an organism,
scientists use many
modern tools:
What happens when you find an
unknown organism?
• 1. Morphology describes
the physical
characteristics of an
organism.
• Typically, this is enough
information to place the
organism within a domain
and kingdom.
• Example: Presence of a
nucleus places the
organism in Domain
Eukarya
Fill It In …
WORD HELP!
“Morph” means ___________
“ology” means ___________
What happens when you find an
unknown organism?
• 2. DNA and biochemical
analysis allow scientists
to test less visible, but
distinguishing,
characteristics.
• Example: Gram staining a
bacteria cell allows
scientists to distinguish
between archaea and
prokarya.
What happens when you find an
unknown organism?
• 3. Comparing embryology
allows scientists to group
organisms that share
common fetal development
• Example: the diagram below
would suggest the last two
organisms are most closely
related.
What happens when you find an
unknown organism?
• 4. Evolutionary phylogeny
describes the evolutionary
relationships between organisms.
• These relationships are deduced
based on shared traits that may
have been passed from ancestor to
new species.
• Traits may include physical traits
(ex. presence of jaws), or may be
genetic traits (shared genes).
• These relationships can be
illustrated in a phylogenetic tree or
cladogram:
Fill It In …
In this cladogram, what
kingdom is most
closely related to
animals?
What kingdom evolved
first?
From what kingdom did
plants evolve?
Fill It In …
The four things we can compare to classify:
1.
2.
3.
4.
Check Yourself!
1.
2.
3.
4.
Who first officially classified organisms?
What was the contribution of Linnaeus to taxonomy?
What are the two parts of a scientific name?
What are the domains used in the current classification
system?
5. How many kingdoms are used in the current
classification system?
6. What is a dichotomous key?
7. What 4 modern tools are used to classify a newly
discovered organism?
Check Yourself!
1. Who first officially classified organisms?
ARISTOTLE
Check Yourself!
2. What was the contribution of Linnaeus to taxonomy?
GROUPED RELATED ORGANISMS
CREATED BINOMIAL NOMENCLATURE
Check Yourself!
3. What are the two parts of a scientific name?
GENUS + SPECIE
Check Yourself!
4. What are the domains used in the current classification
system?
ARCHEA
BACTERIA
EUKARYA
Check Yourself!
5. How many kingdoms are used in the current
classification system?
SIX
Check Yourself!
6. What is a dichotomous key?
TOOL THAT USES A SERIES OF PAIRED
STATEMENTS AND VISIBLE CHARACTERISTICS TO
HELP IDENTIFY UNKNOWN ORGANISMS
Check Yourself!
7. What 4 modern tools are used to classify a newly
discovered organism?
MORPHOLOGY
BIOCHEMICAL ANALYSIS
EMBRYOLOGY
EVOLUTIONARY PHYLOGENY